Store it charged. Its always best to keep them charged. Never let them get completely flat. When I'm not using mine I store it charged and about every 2 weeks I'll put it to trickle charge for a little while to stay topped up (not that it losses much charge anyway). Also to I've heard that if not used for a couple months their capacity can reduce, that's why I keep charging it every so often to keep it working.
Hang around......we'll talk some more